Outlet screw assembly for an air maintenance tire

ABSTRACT

An air maintenance tire assembly includes an air pumping passageway located within a tire sidewall to generate compressed air. An outlet screw assembly includes an elongate screw body residing within a profiled sidewall bore. The screw body extends through an axial span of the first sidewall to the tire cavity to conduct air from the sidewall air passageway to the tire cavity. The screw body has enlarged sectional end components to deter radial dislodging of the screw body from the sidewall bore during operation.

FIELD OF THE INVENTION

The invention relates generally to air maintenance tires and, morespecifically, to such tires having an air pumping sidewall passagewayand an outlet air passage assembly for conducting compressed air fromthe sidewall passageway into a tire cavity.

BACKGROUND OF THE INVENTION

Normal air diffusion reduces tire pressure over time. The natural stateof tires is under inflated. Accordingly, drivers must repeatedly act tomaintain tire pressures or they will see reduced fuel economy, tire lifeand reduced vehicle braking and handling performance. Tire pressuremonitoring systems have been proposed to warn drivers when tire pressureis significantly low. Such systems, however, remain dependent upon thedriver taking remedial action when warned to re-inflate a tire torecommended pressure. It is a desirable, therefore, to incorporate anair maintenance pumping system within a tire that will maintain tire airpressure to compensate for any reduction in tire pressure over timewithout the need for driver intervention.

Such air maintenance pumping systems require an outlet assembly forconducting compressed air from the pumping mechanism into a tire cavity.It is desirable, therefore, to incorporate an outlet assembly for suchpurpose into the air maintenance tire assembly that is secure, reliableand readily repaired in the event that repair becomes necessary.

SUMMARY OF THE INVENTION

In one aspect of the invention, an air maintenance tire assemblyincludes an air pumping passageway located within a tire sidewall togenerate compressed air. An inlet air passage screw assembly is insertedinto a sidewall bore and through the tire sidewall to the tire cavityand conducts air from outside the tire to a regulator positioned withinthe tire cavity. An outlet screw assembly includes an elongate screwbody residing within a profiled sidewall bore. The screw body extendsthrough an axial span of the first sidewall to the tire cavity toconduct air from the sidewall air passageway to the tire cavity. Thescrew body has a T-block insert from which one or more projecting arm(s)extend, the projecting arm fitting within a sidewall air pumpingpassageway to conduct compressed air from the sidewall air passageway toa screw body internal air pathway.

In another aspect, the T-block insert seats within a receptacle bodyconnected to a radially outward end of the screw body, the receptaclebody having a relatively large cross-sectional dimension to inhibit thescrew body pulling through the tire sidewall during operation.

According to a further aspect, the assembly includes a valve housing ata radially inward end of the screw body residing within the tire cavity.A valve mechanism seats within the valve socket, the valve mechanismopening to conduct air from the internal air pathway of the screw bodyinto the tire cavity and closing to prevent a backflow of air from thetire cavity into the internal air pathway of the screw body.

The valve housing has, in an additional aspect of the invention, anoutwardly projecting peripheral flange abutting the tire inner liner,peripheral flange to deter a radially outward pull out of the screw bodyfrom the sidewall bore.

DESCRIPTION

“Aspect ratio” of the tire means the ratio of its section height (SH) toits section width (SW) multiplied by 100 percent for expression as apercentage.

“Asymmetric tread” means a tread that has a tread pattern notsymmetrical about the center plane or equatorial plane EP of the tire.

“Axial” and “axially” means lines or directions that are parallel to theaxis of rotation of the tire.

“Chafer” is a narrow strip of material placed around the outside of atire bead to protect the cord plies from wearing and cutting against therim and distribute the flexing above the rim.

“Circumferential” means lines or directions extending along theperimeter of the surface of the annular tread perpendicular to the axialdirection.

“Equatorial Centerplane (CP)” means the plane perpendicular to thetire's axis of rotation and passing through the center of the tread.

“Footprint” means the contact patch or area of contact of the tire treadwith a flat surface at zero speed and under normal load and pressure.

“Groove” means an elongated void area in a tread that may extendcircumferentially or laterally about the tread in a straight, curved, orzigzag manner. Circumferentially and laterally extending groovessometimes have common portions. The “groove width” is equal to treadsurface area occupied by a groove or groove portion, the width of whichis in question, divided by the length of such groove or groove portion;thus, the groove width is its average width over its length. Grooves maybe of varying depths in a tire. The depth of a groove may vary aroundthe circumference of the tread, or the depth of one groove may beconstant but vary from the depth of another groove in the tire. If suchnarrow or wide grooves are substantially reduced depth as compared towide circumferential grooves which the interconnect, they are regardedas forming “tie bars” tending to maintain a rib-like character in treadregion involved.

“Inboard side” means the side of the tire nearest the vehicle when thetire is mounted on a wheel and the wheel is mounted on the vehicle.

“Lateral” means an axial direction.

“Lateral edges” means a line tangent to the axially outermost treadcontact patch or footprint as measured under normal load and tireinflation, the lines being parallel to the equatorial centerplane.

“Net contact area” means the total area of ground contacting treadelements between the lateral edges around the entire circumference ofthe tread divided by the gross area of the entire tread between thelateral edges.

“Non-directional tread” means a tread that has no preferred direction offorward travel and is not required to be positioned on a vehicle in aspecific wheel position or positions to ensure that the tread pattern isaligned with the preferred direction of travel. Conversely, adirectional tread pattern has a preferred direction of travel requiringspecific wheel positioning.

“Outboard side” means the side of the tire farthest away from thevehicle when the tire is mounted on a wheel and the wheel is mounted onthe vehicle.

“Peristaltic” means operating by means of wave-like contractions thatpropel contained matter, such as air, along tubular pathways.

“Radial” and “radially” means directions radially toward or away fromthe axis of rotation of the tire.

“Rib” means a circumferentially extending strip of rubber on the treadwhich is defined by at least one circumferential groove and either asecond such groove or a lateral edge, the strip being laterallyundivided by full-depth grooves.

“Sipe” means small slots molded into the tread elements of the tire thatsubdivide the tread surface and improve traction, sipes are generallynarrow in width and close in the tires footprint as opposed to groovesthat remain open in the tire's footprint.

“Tread element” or “traction element” means a rib or a block elementdefined by having a shape adjacent grooves.

“Tread Arc Width” means the arc length of the tread as measured betweenthe lateral edges of the tread.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described by way of example and with reference tothe accompanying drawings in which:

FIG. 1 is a perspective view of a tire with pump channels using theinlet air passageway screw assembly with regulator and bi-directionaloutlet screw assembly.

FIG. 2 is a side view of the tire with pump channels using the inlet airpassage screw assembly with regulator and outlet screw assembly. Tirerotation is counter-clockwise and air flow is clockwise.

FIG. 3 is a side view of the a tire with pump channels using the inletair passageway screw assembly with regulator and bi-directional outletscrew assembly. Tire rotation is clockwise and air flow iscounter-clockwise, showing the bi-directionality of the air maintenancesystem.

FIG. 4 is a partially sectioned perspective view showing the air passageinlet screw assembly with a regulator exploded.

FIG. 5 is a partially sectioned section perspective view showing the airpassage inlet screw assembly with a regulator exploded.

FIG. 6 is a perspective view of the air passage inlet screw assembly.

FIG. 7 is a section view of the inlet taken from FIG. 6.

FIG. 8 is an exploded perspective view of the inlet assembly.

FIG. 9A is a section view taken from FIG. 5 showing air passing throughthe filter and entering the duck valve.

FIG. 9B is a section view showing air passing through the duck valve andentering a pump channel enroute to the outlet.

FIG. 10 is a partially sectioned perspective view showing thebi-directional outlet screw assembly exploded.

FIG. 11 is a partially sectioned perspective view showing thebi-directional outlet screw assembly installed.

FIG. 12 is a perspective view of the bi-directional outlet screwassembly.

FIG. 13 is a section view of the outlet screw assembly taken from FIG.12.

FIG. 14 is an exploded perspective view of the bi-directional outletscrew assembly.

FIG. 15A is a section view taken from FIG. 11 showing air coming fromthe pump channel, entering the outlet and entering the duck valve.

FIG. 15B is a section view showing air passing through the duck valveand entering the tire cavity.

FIG. 16 is a side view of the tire with pump channels using an airpassage screw inlet with a regulator and a mono-directional outletscrew. Tire rotation is counter-clockwise and air flow is clockwise.

FIG. 17 is a perspective view of the mono-directional outlet screwassembly.

FIG. 18 is a section view of the mono-directional outlet taken from FIG.17.

FIG. 19 is an exploded perspective view of the mono-directional outletscrew assembly.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1 through 5, a tire assembly 10 includes a tire 12,and a tire-based peristaltic pump assembly 14. The tire 12 mounts inconventional fashion to a rim 13 for vehicle use. The tire is ofconventional construction, having a pair of sidewalls 16, 18 extendingfrom opposite bead areas 20, 22 to a crown or tire read region 24. Thetire and rim enclose a tire cavity 28 that is defined by a tire innerliner 26.

As seen from FIGS. 1 through 5, the peristaltic pump assembly 14includes an annular air passageway 19 formed within one of the tiresidewalls 16, 18. Alternatively, a pump assembly 14 may be placed inboth sidewalls if desired. The passageway 19 is enclosed by its hostsidewall and may extend 360 degrees about the circumference of thesidewall for bi-directional capability or, alternatively, 180 degreesfor mono-directional capability. The air passageway is surrounded byresilient sidewall material such that the passageway 19 may be placedsegment by segment into a flattened condition subject to external forceand, upon removal of such force, returns to an original conditiongenerally circular in cross-section. The passageway 19 has a diametersufficient to operatively push a volume of air sufficient for thepurposes described herein. Air “passageway” 19 is also referred toherein as an air “channel”. The passageway or channel 19 is enclosedwithin a tire sidewall and functions to provide an air pumping devicefor pressurizing internal air flow around the passageway 19 as the tirerotates against a ground surface.

The operational principle of the peristaltic pumping tube in a tire forthe purpose of maintaining tire air pressure is described in issued U.S.Pat. No. 8,113,254, hereby incorporated herein by reference in itsentirety. As disclosed, a peristaltic pumping tube is incorporate withina tire sidewall. As disclosed by the above patent incorporated byreference herein, a T-shaped inlet device is affixed inline with anannular pumping tube and conducts air from outside of the tire into thepumping tube for pressurization. A T-shaped outlet device, positionedopposite the inlet device, is likewise affixed inline with the pumpingtube. The outlet device conducts pressurized air from the pumping tubeinto the tire cavity to maintain cavity pressure at a desired level.Functionally, the pumping tube is located in a high flex region of thesidewall. So located, the pumping tube compresses segment by segmentfrom an expanded diameter to a substantially reduced diameter responsiveto a bending strain introduced into the sidewall from a rolling tirefootprint. Pressurized air is thereby forced segment by segment alongthe air tube and directed as needed into the tire cavity for pressuremaintenance.

The subject invention pump works pursuant to the same principle as thepatent but uses an integral air passageway formed within and by the tiresidewall instead of a separate tube placed inside a sidewall groove.

While working well, the inlet and outlet devices taught by U.S. Pat. No.8,113,254 are relatively large and their incorporation into andoccupancy within a tire sidewall introduces structural disruption in thesidewall. Moreover, the inlet and outlet devices are difficult to accessand repair should that become necessary. Finally, the inlet and outletdevices of the patent are not easily affixed to the air tube andreplacing such devices within a tire sidewall could prove problematic.

The peristaltic pump assembly 14 of the subject invention provides aninlet air passageway screw assembly and an outlet air passagewayassembly. Such assemblies are alternatively referred to herein as “inletscrew assembly” and “outlet screw assembly” from a preferred assembly ofsuch assemblies through a tire sidewall bore by twisting or screwing.Air from outside the tire is routed by the inlet air passageway assembly36 to a regulator 30 mounted to the tire inner liner 26. The regulator30 is of a type commercially available and includes a pressuremonitoring sensor that measures air pressure within the tire cavity 28.The regulator 30 opens when air pressure within the cavity 28 fallsbelow a threshold level and allows air from the inlet assembly 36 topass through regulator outlet conduits 32, 34 to the air passageway 19If air pressure within the cavity 28 is at or above the threshold, airto the pumping passageway 19 is blocked. A suitable representativeregulator manufacturer is Eaton Corporation and a suitable regulatorconfiguration is as shown and described in PCT Patent Application No.PCT-US2015/010441, filed on Jan. 15, 2015, and entitled SELF-INFLATINGTIRE AIR REGULATOR, hereby incorporated herein in its entirety.

An outlet screw assembly 74 mounts to the tire at a location oppositethe inlet air passageway assembly 36 as seen in FIGS. 1 through 3. Theoutlet screw assembly 74 directs pressurized air from the air passageway19 into the tire cavity 28. Air is forced segment-by-segment along theair passageway 19 from pressure on the air passageway is exerted fromrotation of the tire against a road surface. In FIG. 2, it is shown thata counter clockwise rotation of the tire against a road surface forcesair in a clockwise direction along the air passageway 19. Air along thepassageway 19 is thus pressurized and forced through the outlet assembly74 and into the tire cavity. In FIG. 3, bi-directionality of the 360degree air passageway is demonstrated as the tire rotates in a clockwisedirection, forcing air along the passageway in a counter-clockwisedirection.

Referring to FIGS. 4 through 8, the inlet air passageway assembly 36 andits assembly into the tire sidewall 16 is shown in detail. The airpassageway assembly 36 is referred to herein as an “air passageway screwassembly” or an “air passageway screw” due to the torque applied to theassembly during its insertion through a tire sidewall. The regulator 30has a housing mounted against the tire inner liner 26. The regulator 30provides an internally threaded socket 31 positioned between theconduits 32, 34. The inlet air passageway assembly 36 is shown in detailby FIGS. 6 through 8. A porous or cellular air filter 38 in the form ofa cylindrical body is used to clean air drawn into the system fromoutside the tire. An elongate generally cylindrical, dumbbell-shapedscrew body 48 is preferably of a unitary construction. The body 48 maybe formed from a suitable rigid material such as plastic resin. Thescrew body 48 includes a cylindrical, relatively large-diameter, filterhousing 44, a relatively small-diameter tubular midsection portion 46also referred herein as a “shank” portion, and a mid-sizedlarge-diameter cylindrical valve housing 48. The filter housing 44 isbowl-shaped and receives therein the filter 38. Internal threads at 58of the housing 44 engage external threads 56 of a cap 40. The cap 40threads into the housing 42 to enclose the filter 38. The cap 40 has anaccess opening 41 allowing air to pass into the housing 42 from outsidethe tire. Such inlet air passes through and is cleansed by the filter38.

The screw body 48 forms an axial air pathway 54 through the body asshown. A check valve 50 is provided in the preferred form of a duck billvalve but other valve configurations may be used if desired. The valve50 has a peripheral annular retaining flange 60 and is sized for receiptinto a valve socket 63 positioned at a lower end of valve housing 48.The flange 60 of the valve 50 seats in a supported fashion within thehousing socket as shown in FIG. 7. The retainer ring 52 is cylindricaland externally threaded to engage internal screw threads within thevalve housing socket 63. Once inserted, the retainer ring 52 abutsagainst the valve flange 60 to retain the valve 50 in a seated positionwithin the socket 63 of the housing 48.

The assembled inlet air passageway assembly 36 is shown FIGS. 4, 6 and7. The assembly 36 inserts and attaches to the tire sidewall 16 by meansof screw insertion of the assembly 36 through a profiled bore 64extending through the sidewall as shown. The profiled bore 64 includes alarger diameter filter housing-receiving bore portion 66 and a tubularinner bore shank segment 68 sized nominally larger in section than thescrew body shank 46 of the inlet air passageway assembly 36. The innerbore segment 68 is diametrically sized larger than the screw body shank46 to allow the valve housing at the terminal inward end of the screwbody shank to be screwed through the bore during assembly of theassembly 36 through the sidewall. The assembly 36 is inserted into thebore 64 in a post-cure procedure. Once assembled through the bore 64,the valve housing 48 by means of external screw threads 62 threads intothe socket 31 of the regulator 30. The regulator is thus securelycoupled to the inlet air passageway assembly 36 and, in particular, thescrew body 48. The air pathway 54 extending through the assembly 36 isthus placed in air flow communication with the regulator 30. Air intakefrom outside of the tire passes through the filter 38, the air pathway54, and the duck valve 50 to enter into the regulator 30.

FIG. 9A illustrates by arrows 70 the air flow path in the closedposition with duck valve 50 closed or shut. The valve closes by membraneconstriction when air is not drawn through the valve from outside thetire. The regulator shuts off air flow into the tire whenever the airpressure within the tire is at or above the desired pressure level. Airintake into the and through the regulator from the inlet air passagewayassembly 36 is blocked and the duck valve 50 remains in a closedposition until air flow through the regulator starts. When air pressureis low in the tire, the regulator opens and allows intake air to passthrough the regulator conduits 32, 34. In FIG. 9B, the valve 50 is shownin the open condition, allowing air flow (arrows 72) to pass through thefilter 38, along the air pathway 54, through the duck valve 50, and intothe regulator 30. The open condition is controlled by the regulatorwhich opens whenever the air pressure within the tire, as sensed by theregulator pressure sensor, falls below a desired level. The regulator 30allows air to pass into either outlet conduit 32 or outlet conduit 34,depending on the direction of tire rotation. Air from conduit 32 or 34is introduced into the annular groove within the tire sidewall formingthe tire air passageway 19. Rotation of the tire forces the air alongthe groove 19 toward an outlet assembly and through the outlet assemblyinto the tire cavity. Air pressure within the tire cavity is therebyraised to the desired level.

It will be seen from FIGS. 4 through 9B that the air passageway assembly36 is in the form of a screw that is twisted through the sidewall boreduring sidewall attachment and then subsequently screws into theregulator 30. The peristaltic pump assembly 14 requires an air passagefrom the surrounding atmospheric air through the tire sidewall in orderto replace the lost air from the tire. The air passageway assembly orscrew 36 provides a filter to allow clean air to enter the AMT system,and to the tire. Furthermore, the system incorporates additionalfunctionality in housing an air filter, mounting the regulator to thetire. The check valve 82 incorporated within the air passageway assembly36 operates as a guard against back flow of air from the AMT system tothe atmosphere surrounding the tire. The valve 82 allows air to flowinto the tire but prevents back flow of air from the tire.

The screw assembly body 42 is pushed and twisted from outside of thetire through the molded bore (hole) 64. The shape of the bore 64 matchesthe air passage screw assembly shape. Once through the tire sidewall andin position, the valve 50 and housing 52 are installed into the housing48, and the screw assembly is then screwed into the regulator 30.Lastly, the filter 38 is enclosed within housing 42 by the cap 40. Thedumbbell general shape of the screw assembly prevents its detachmentfrom the tire sidewall bore in either inward or outward directions. Thefilter housing 44, on the outside acts as an anchor to prevent theweight of the pressure regulator at high speeds to pull the airpassageway assembly 36 through the tire sidewall. Likewise, theregulator 30 and its relative large size in relation to the diameter ofthe sidewall bore 64 prevents the regulator from being pulled or pushedback through the bore 64.

As described above, center of the air passageway screw 36 is hollowforming the air pathway 54. Air is thus allowed to flow from a radiallyouter end of the screw assembly to a radially inner end, from the filter38 to the pressure regulator 30. The check valve 50 is mounted to theradially inward end closest to the regulator 30 and operates as afail-safe to prevent air from escaping back from the tire cavity throughthe regulator and the air passageway assembly.

While the inlet air passageway assembly 36 is shown attached to thelower region of a tire sidewall, it may alternatively be placed in achafer, shoulder or tread region. The filter 38 is used to clean airpassing through the assembly 36 but may be dispensed with if desired.Also, the check valve 50 may be removed from the assembly if its failsafe function is not needed.

Referring to FIGS. 10 through 14, an air outlet screw assembly 74 isshown for use by the subject AMT system. The outlet screw assembly 74provides an outlet air passage from the pump groove 19 through orpartially through the tire sidewall 16. Compressed air from the pumpgroove 19 is thereby directed to the tire cavity 28 to bring the cavityair pressure to a desired level. Thus, the assembly 74 acts primarily asa single air passage to allow compressed air from two pump channels inthe pump assembly bi-directional configuration or a single pump channelin the mono-directional configuration. The outlet screw assembly 74furthermore provides a fail-safe valve sub-assembly that may be securedto the tire sidewall.

The outlet screw assembly 74 includes an elongate tubular outlet screwbody 76 formed of suitably rigid material such as plastic. The body 76screw assembles to a valve bottom screw housing 78 which, in turn,screws into a retainer nut 80. A check valve 82 such as a duck valve ishoused and seats within the screw housing 79, An assembly screw 84inserts into a T-block 86 which inserts into an upper housing 102 of thescrew body 76. The upper housing 102 is bowl-shaped having a hollowinterior. The assembly screw 84 has an externally threaded shaft 90 thatinserts through a through bore 94 of the T-block 86 and into aninternally threaded socket of the screw body 76. A shank segment of theassembly screw 84 has an air passageway positioned to allow air entrywhen the assembly screw 84 is in the inserted position within screw body76 as will be seen in FIG. 13.

The T-block 86 is a hollow cube-shaped body having the through bore 94extending from a top surface through the block to a bottom surface. Twocylindrical arms 96, 98 extend in opposite directions from the T-block86, each arm having an axial air passageway 100 extending therethrough.Air passing through passageways 100 enters the T-block internal throughbore 94 and passes along the bore 94 to a lower side of the T-block. TheT-block is shaped as a cube and fits within a hollow screw bodyreceptacle 102. The body 76 tapers along a mid-segment shank portion 104to an externally threaded lower cylindrical shaft 106. A center axialair passageway 108 extends down through the screw body 76 from thereceptacle 102 at a top or outer end to a lower end of the shaft 106.The receptacle 102 is formed having two U-shaped openings 110, 112 inopposite sidewalls. The openings receive the arms 96, 98 of the T-blockupon insertion of the T-block 86 into receptacle 102.

The externally threaded shaft 106 screws into the valve housing 78. Thevalve housing 78 has a annular outward projection flange 114 and athrough air passageway 116. The valve housing 78 has a cylindricalmid-segment 120 hexagonal in external configuration and a lowerexternally threaded post 118. A centering post 122 projects downwardfrom the lower end of the valve housing 78. The check valve 124 includesan annular upper flange 124 and a center axial air passageway 126extending end to end through the valve body. The valve 82 opens andcloses at membrane 128 to allow or prevent the passage of air from thesidewall groove 19 down through the valve 82 and into the tire cavity28. The valve 82 is seats against a lower end of the bottom screw 78with the annular valve flange 124 seated against an external end surfaceof the shank end 118. The valve 82 seats over the post 122. After thevalve 182 is in seated position over the post 122, the retainer nut 80screws over the shank 118 to hold the valve 82 in place. An internalshoulder within the nut axial through bore 130 holds the valve byengagement with the valve annular flange 124 as seen in FIG. 13. The hexconfiguration of the nut 80 assists in tightening the nut body 132 tothe shank 118. A tubular end post protrusion 134 at the bottom of thenut 80 extends and assists to direct air passing from top to bottomthrough the outlet screw assembly into the tire cavity. The components74, 76, 78, 80 and 82 have axial passageways that align in the assembledcondition to create an air passageway from the arms 96, 98 to the tirecavity 28.

Attachment of the outlet screw assembly 74 through a tire sidewall 16and operation of the assembly 74 will be understood from FIGS. 10, 11,15A and 15B. The screw assembly 74 inserts through a profiled bore 138formed within the sidewall 16. The bore 138 has a radially outwardenlarged-diameter region 140 into which the screw body receptacle 102 isseated and a radially inward bore shank 142 receiving the screw bodyshaft 106. After the screw body 76 is inserted through the bore 138, thevalve bottom screw 78 couples to the shaft 106 by threaded engagement.The valve 82 is then placed into seated position over a lower end of thethreaded shank 118 and the nut 80 is screwed onto shank 118 to hold thevalve in position. The components 78, 80, 82 thus reside within the tirecavity 28 and may be readily replaced in the event repair becomesnecessary. The arms 96, 98 extending from the T-block 86 upon insertionof assembly 74 to the bore 138 are placed within opposite ends of theair passageway 19. Air passing from the air passageway 19 of thesidewall 16 is thus directed into the T-block through the passageways100 of the arms 96, 98. From the T-block 86 the air can pass axiallyinward through the outlet screw assembly 74.

FIG. 15A illustrates the outlet screw assembly 74 in the closedcondition, with valve 128 closed. This condition exists when the airpressure within the tire cavity 19 is at or above a desired level. Theregulator (previously described) 30 functions to sense tire pressurewithin the cavity 19 and to block air flow into the pumping sidewallgroove 19 when no further air is required by the tire cavity 19 tomaintain desired pressure. In the closed position of FIG. 15A, theclosed valve 128 additionally functions to prevent back flow of air fromthe tire cavity 28 through the outlet assembly 74 and into the sidewallgroove 19.

FIG. 15B represents the outlet screw assembly 74 in the open position,conducting pressurized air from the sidewall groove 19 through theassembly 74 and into the tire cavity 28. The regulator 30, sensing tirepressure within the cavity 19 to be lower than desired, opens to allowair to flow from inlet air passageway assembly 36 into the tire sidewallgroove 19. The groove 19 progressively forces the air along the groove19 as the tire rotates until the air reaches and enters the outlet screwassembly 74. The assembly 74 conducts the air down through aligned axialpassageways of the assembly components, through the open valve 128, andinto the tire cavity 28. Once air pressure within the cavity is raisedto the desired preset level, regulator 30 closes off further air inputinto the groove 19 and pumping of air by the groove 19 ceases.

It will be appreciated that the 360 degree configuration of the sidewallgroove 19 makes the air pumping assembly 14 bi-directional; that is, airis pumped along the groove 19 in both directions, alternatively,depending on whether the tire is rotating forward or backward. In eitherdirection the outlet screw assembly 74 functions to admit air into thetire cavity. The assembly arms 96, 98 are connected to ends of the airpumping groove 19 and thus conduct air flow in a bi-directional mannerinto the assembly 74 and therefrom into the tire cavity 28. Shouldmono-directional air pumping be desired, the system may be altered intoa mon-directional configuration as shown in FIG. 16, and FIGS. 17-19. Inthe mono-directional system, the groove 19 within the tire sidewall 16extends in an arcuate path of 180 degrees. The groove 19 extends betweenthe location of the inlet air passageway assembly 36 and the outletscrew assembly 74. Air flows into the system through the assembly 36 aspreviously described, through regulator 30, is pumped along the groove19 as the tire rotates (in a single direction only), and exits thegroove 19 through the outlet screw assembly 74. Mono-directional airflow along the groove 19 is thus used in the mono-directional systemconfiguration, to re-inflate the tire cavity to a desired air pressurein the same manner previously described with regard to thebi-directional system.

FIGS. 17, 18 and 19 show the components assembled to form the outletscrew assembly 138 for a mono-directional system. The components aregenerally the same as previously described in reference to FIGS. 12through 14 with the exception of modification to block 92 and screw body76. Like numerals that are previously used in the bi-directional systemare applied in the mono-directional system of FIGS. 17 through 19 whereappropriate. In FIGS. 17 through 19, it will be seen that the block 92is constructed to provide a single arm extension for positioning withinthe sidewall groove 19. Accordingly, the bowl-shaped receptacle 102receiving the block 92 during assembly only requires a single opening112 to receive the lone arm 98. Assembly of the outlet screw assembly 76through a tire sidewall bore proceeds as previously explained.

From the foregoing, it will be seen that the subject outlet screwassembly 74 provides an air outlet passage from the enclosed pumpchannel 19 at least partially through the tire structure, typically thesidewall 16, to provide compressed air to enter into the tire cavity 28.The air passage screw assembly 74 acts primarily as a single air passageto allow the compressed air from either two pump channels in abi-directional system or a single pump channel in a mono-directionalsystem entering the tire cavity 28. Furthermore, the outlet screwassembly 74 provides additional functionality in providing a check valveto prevent undesirable backflow of air from the tire cavity and the lossof air pressure such backflow would cause.

The pump outlet screw assembly 74 consists of a single piece body 76that can be inserted into the tire structure such as sidewall 16 aftertire curing. The body 76 will be pushed form the outside through amolded hole or bore 116 in the tire. The shape of the bore 116 matchesthe air passageway screw body 76 shape. Once through the tire and inposition, the bottom valve screw 78 is fixedly attached and the valve82, retainer nut 84 are attached. The T-block 86 is then installed.

The center pathway of the outlet screw assembly once fully assembled ishollow to allow airflow from the pumping passageway 19 to the tirecavity 28. The T-block 86 avoids an air flow from one side of the 360degree air passageway 19 to the other by having incorporated within theassembly screw 84 an internal directional valve 87. See FIG. 13. Asshown, air entering the T-block either through arm 96, 98 encounters aninternal valve 87 within the T-block. The valve 87 directs air flow downthrough the outlet screw assembly toward the valve 128 but prevents airfrom flowing through from the T-block through the opposite arm 96, 98and back into the pumping passageway 19.

The large diameter of the screw body receptacle 102 on the outside actsas an anchor to prevent the weight of the screw at high speeds to pullin from the tire sidewall. Likewise, valve bottom screw 78 having wideperipheral flange 114 acts to prevent the screw from being pulled orpushed out. The receptacle 102 has an internal thread for receiving theassembly screw shaft 90. The shaft 106 in turn screws into the valvebottom screw socket 116. The bottom screw 78 can thus compensate forvariations in tire sidewall thickness gauge. The bottom screw 78 will befixed with a requisite torque to the screw body 76 to reach a propersitting and to prevent air leakage. The check valve 82 prevents air fromleaking out of the tire as described above. The outside of the screwbody 76 allows it to screw into position within the bore 116 duringassembly.

The outlet screw assembly 74 may be attached alternatively to a tirechafer, shoulder or tread. It may be used without the check valve 82 ifsuch a function is not deemed necessary.

Variations in the present invention are possible in light of thedescription of it provided herein. While certain representativeembodiments and details have been shown for the purpose of illustratingthe subject invention, it will be apparent to those skilled in this artthat various changes and modifications can be made therein withoutdeparting from the scope of the subject invention. It is, therefore, tobe understood that changes can be made in the particular embodimentsdescribed which will be within the full intended scope of the inventionas defined by the following appended claims.

What is claimed is:
 1. An air maintenance tire assembly comprising: atire having a tire cavity defined by an inner liner, the inner linerbounded by first and second sidewalls extending to a tire tread region;the first sidewall having an elongate sidewall air passageway, the airpassageway operatively located to compress segment by segment from anexpanded diameter to a substantially reduced diameter responsive to abending strain introduced into the first sidewall from a rolling tirefootprint to compress air along the sidewall air passageway; a regulatorassembly positioned adjacent the tire inner liner operative to controlpressurized air flow into the tire cavity; an inlet air passagewayassembly connecting to the first sidewall and operative to conduct airfrom outside the tire into the regulator assembly; an outlet screwassembly comprising an elongate screw body extending through an axialspan of the first sidewall and, the screw body having an elongateinternal air pathway operative to conduct air from the sidewall airpassageway to the tire cavity; the screw body having at least oneoutwardly projecting arm at a radially outward end, the projecting armfitting within the sidewall air passageway and having an axial arm airpassageway operative to conduct compressed air from the sidewall airpassageway to the screw body internal air pathway.
 2. The airmaintenance tire assembly of claim 1, wherein further comprising areceptacle body connected to a radially outward end of the screw body,the receptacle body housing a T-block insert body; wherein the at leastone outwardly projecting arm is connected to the T-block insert body andprojects from the T-block insert body through a sidewall opening of thereceptacle body.
 3. The air maintenance tire assembly of claim 2,wherein the T-block insert body has a hollow central chamber in airfluid communication with axial arm air passageway.
 4. The airmaintenance tire assembly of claim 3, wherein the screw body resideswithin a sidewall bore extending at least partially through the firstsidewall; wherein the receptacle body has a larger-in-section dimensionand wherein the receptacle body resides within a larger-in-sectionoutward region of the sidewall bore; and wherein the screw body has anarrower neck segment of a smaller-in-section dimension residing withina smaller-in-section inward region of the sidewall bore.
 5. The airmaintenance tire assembly of claim 4, further comprising a valve housingat a radially inward end of the screw body, the valve housing residingwithin the tire cavity; and a valve mechanism seated within a valvesocket, the valve mechanism opening to conduct air from the internal airpathway of the screw body into the tire cavity and closing to prevent abackflow of air from the tire cavity into the internal air pathway ofthe screw body.
 6. The air maintenance tire assembly of claim 5, whereinthe valve housing has an outwardly projecting peripheral flange abuttingthe tire inner liner, peripheral flange operative to deter a radiallyoutward pull out of the screw body from the sidewall bore.
 7. An airmaintenance tire assembly comprising: a tire having a tire cavitydefined by an inner liner, the inner liner bounded by first and secondsidewalls extending to a tire tread region; the first sidewall having anelongate sidewall air passageway, an air tube operatively located tocompress segment-by-segment from an expanded diameter to a substantiallyreduced diameter responsive to a bending strain introduced into thefirst sidewall from a rolling tire footprint to compress air along theair passageway; a regulator assembly positioned within the tire cavityand operative to control compressed air flow into the tire cavity; aninlet air passageway assembly connecting to the first sidewall andoperative to conduct air from outside the tire into the regulatorassembly; an outlet screw assembly comprising an elongate screw bodyextending through an axial span of the first sidewall to the tire cavityand the screw body having an elongate internal air pathway operative toconduct air from the sidewall air passageway to the tire cavity; thescrew body having a T-block body at a radially outward end, the T-blockbody having at least one outwardly projecting arm fitting within thesidewall air passageway and having an axial arm air passageway operativeto conduct compressed air from the sidewall air passageway to the screwbody internal air pathway.
 8. The air maintenance tire assembly of claim7, wherein the T-block body seats within a receptacle body connected toa radially outward end of the screw body, the receptacle body has alarge cross-sectional dimension and wherein the receptacle body resideswithin a wide region of the sidewall bore, and wherein the screw bodyhas a narrower neck segment of a small cross-sectional dimensionresiding within a narrow region of the sidewall bore.
 9. The airmaintenance tire assembly of claim 8, further comprising a valve housingat a radially inward end of the screw body, the valve housing residingwithin the tire cavity; and a valve mechanism seated within a valvesocket, the valve mechanism opening to conduct air from the internal airpathway of the screw body into the tire cavity and closing to prevent abackflow of air from the tire cavity into the internal air pathway ofthe screw body.
 10. The air maintenance tire assembly of claim 9,wherein the valve housing has an outwardly projecting peripheral flangeabutting the tire inner liner, peripheral flange operative to deter aradially outward pull out of the screw body from the sidewall bore.